Generally, as illustrated in FIG. 7, a medium conveyance mechanism 101 conveys a gripped medium 4 as illustrated by arrow X, by disposing a drive roller 18 and a following roller 17, disposed at a position facing the drive roller 18, as a pair of conveyance rollers, rotating the drive roller 18 in a W1 direction by a power source (not illustrated), and dragging the following roller 17 around in a W2 direction.
Further, the following roller 17 includes a pressing mechanism that presses, by a spring 103, as illustrated by arrow Y, in order to accommodate changes in the thickness of the gripped medium 4.
As a pressing mechanisms, a pressing mechanism configured by a compression spring that presses a shaft of the following roller 17 (see for example Japanese Patent Application Laid-Open (JP-A) No. 9-67042), a pressing mechanism configured by fixing a plate spring by a screw that presses against the shaft of the following roller 17 (see for example JP-A No. 1-150651), or a pressing mechanism wherein a pivot shaft is passed through a coil portion of a torsion spring and one arm of the torsion spring is fixed whilst the other arm presses the shaft of the following roller 17 (see for example JP-A No. 8-2734) exists.